The latest lens developed by Sigma for its DC range for cropped sensor cameras (APS-C sized sensors) is this fast standard zoom with close focus capability. With a focal length range of 17-70mm and able to focus down to less than eight inches, we take the UK’s first look at how it performs.

Specification

Focal Length 17-70mm

Construction 15/12 elements/groups

Angle of view 72.4º-20.2º (SD format 1.7x crop)

Max Aperture f/2.8-4.5

Min Aperture f/22-f/32

Min focus 20cm/7.9inch

Max magnification 1:2.3

Filter size 72mm

Dimensions 79x82.5mm

Weight 0.455kg

Mount Sigma, Canon, Nikon, Pentax, Minolta.

SRP £269.99

Build and HandlingSupplied with a petal shaped hood, the lens is finished in Sigma’s matt black finish and sports a metal mount. There is an AF/MF switch on the left of the barrel before the 35mm zoom ring, which carries a zoom lock to stop the lens extending during transport. I did not use it, as, although nicely torqued, the lens did not seem to creep during either use or transport. The zoom ring has 20mm of raised ribbing and is marked at 17, 24, 35, 50 and 70mm. As you zoom out to the 70mm mark, the lens extends some 40mm on a double trombone. With the extension, a reproduction ratio scale is revealed on the first tube, a nice touch. Whilst not true Macro, only reaching a ratio of 1:2.3, this close focus capability of only 200mm is very useful.

Double trombones are prone to play but there was none evident in this one and, along with the internal focus mechanism, means the front element does not rotate making filter use far easier.

Autofocussing is fairly quiet for a conventional motor and quick enough to cope with most uses, especially those that this type of lens will be put to. Probably helped by the wide aperture, there was virtually no hunting. Switchover to manual is achieved by the switch that frees up the 20mm manual focus ring, half of which has raised rubber ribbing and is marked with a distance scale in both metres and feet. The front element surround steps up to take the 72mm filters and a bayonet fit hood that has a positive click to hold it in place.

Optical QualityThis lens produced surprisingly good results throughout the focal range although as usual, they were best at the shorter lengths. The one exception being where distortion is concerned and that is by far the best at the longer focal length. At 17mm it measured –5.05% (barrel) whereas the longer end returned 0.32%(pincushion), undetectable by eye.

Resolution figures are pleasing, especially once the lens is stopped down by the odd stop or so and even wide open the visual results are encouraging.

Chromatic aberrations are kept well below the single pixel level throughout the aperture range and across the frame, a commendable performance. Combined with good contrast and the digital coating that Sigma now use to reduce incidences of flare and ghosting, neither of which reared their ugly heads, the lens performed well above the standard ‘kit’ lenses in this focal range.

Woodland scene with the lens set at 30mm. By this length, distortion is no longer visible. ISO400, 1/60sec at f/8.

Backlit snowdrops are a subject that will show any incidence of chromatic aberration up alarmingly but there is no sign in this shot which also shows the lens’s close focus ability. 1/150 at f/10 and ISO100 on 20D with the lens set at 70mm

The lens’s focal range is quite handy. 70mm and 1/320sec at f/8, ISO100.

Click on each comparision photo below to view full size versions

17-70mm set at 17mm and f/8

17-70mm set at 70mm and f/8

17-70mm set at 17mm and f/2.8

17-70mm set at 70mm and f/4.5

Below is our lens test data. To find out how to use these graphs look at this article: How we test lenses

VerdictIn it’s price bracket, this lens can be considered good. It’s one drawback is the distortion at the wide end, but this is one of the easier problems to cure in digital software and being designed purely for digital cameras with cropped sensors will have no effect on film users. The DC/DG coating that Sigma now uses has gone a long way to improving their lens’s contrast and this shows well in this example. The close focus ability of this offering also helps to greatly increase its versatility.

In summary, the positive points of the Sigma 17-70mm f/2.8-4.5 DC Macro are: Excellent close focus ability Good build with no wobbles Good resolution figures overall

The negative points are: Barrel distortion at the wide end AF not as quiet as HSM lenses

Comments

I own this model, and use it as a walkabout lens. I bought it because my previous walkabout lens, which was 28mm at the wide end, often made me wish I had something wider on the camera, and it didn't let in much light. This lens solved both of those problems. With 2.8 at the wide end, it's fast enough in that respect. And although I wish it had a constant aperture of 2.8, 4.5 at the long end hasn't proven to be a great disadvantage, so far (I've owned the lens for four months now). It's true that focusing isn't completely silent, or even nearly silent, but it's not really that noisy either - it's not the noisiest lens in my collection. Might be a consideration if you want to take candids, but since I don't often do that, I haven't found this to be a problem at all. Overall a very nice lens, useful for many purposes. Just don't try action shots - this lens had trouble focusing on a dog that was running very fast. That was more than it could handle. You might want to look at a lens with HSM or USM for that.

I own this model, and use it as a walkabout lens. I bought it because my previous walkabout lens, which was 28mm at the wide end, often made me wish I had something wider on the camera, and it didn't let in much light. This lens solved both of those problems. With 2.8 at the wide end, it's fast enough in that respect. And although I wish it had a constant aperture of 2.8, 4.5 at the long end hasn't proven to be a great disadvantage, so far (I've owned the lens for four months now). It's true that focusing isn't completely silent, or even nearly silent, but it's not really that noisy either - it's not the noisiest lens in my collection. Might be a consideration if you want to take candids, but since I don't often do that, I haven't found this to be a problem at all. Overall a very nice lens, useful for many purposes. Just don't try action shots - this lens had trouble focusing on a dog that was running very fast. That was more than it could handle. You might want to look at a lens with HSM or USM for that.

My friend bought a 17-70 as it seemed good value for money but after buying it, we discovered it was back focused, had no contrast at F5.6 or larger and sharpness as a result was very poor. We went back to the shop and tested 8 other lenses in stock. After 2 hours, we picked the best one but after more testing, it was still 10mm back focused and again, contrast at F5.6 or larger was terrible. Having no idea what to do, we went to our local Sigma service center in Hong Kong to have the lense recalibrated. After two days, we got the lense back and it was still 3mm back focused causing 80% of photos to be out of focus. We spoke to Sigma and what advice did they give "You must use ths lens only in manual focus mode and at f5.6 to get good shots. These lenses are like this, there is nothing more we can do". After given that advice, we swiftly refunded the lens and exchanged it for a canon 17-40.
I don't like to put down any brands but after the experience we had, I really feel I ought to share as I think Sigma are getting away with murder selling the products they do for hard earned money and yet have the cheek to patronise the consumers. I have only ever bought L lenses but on this occasion, reccommened Sigma to my friend as she has a low budget. Boy do I regret it.
To all of you who want a good lens, stick to Canon. I strongly believe those reviewers who claim they have excellent Sigma lenses are total amateurs. It's a bit like writing a car review having never tested a Ferrari. How do you know what is good if you have never tested the best ?...
One more thing, even the shop keeper was not surprised when we went back for an exchange. That just says it all.
In the case of canon, they are an expensive brand but they get it right more of the time. There are bad lenses reaching the shop shelves but far fewer than sigma. I have used canon L's for a while and do some pretty geeky tests before I buy. 80% of lenses are excellent. In the case of Sigma, 80% was unacceptable, 10% was passable, 10% was OK but "OK"
Nb. We used various camera bodies in the tests

My friend bought a 17-70 as it seemed good value for money but after buying it, we discovered it was back focused, had no contrast at F5.6 or larger and sharpness as a result was very poor. We went back to the shop and tested 8 other lenses in stock. After 2 hours, we picked the best one but after more testing, it was still 10mm back focused and again, contrast at F5.6 or larger was terrible. Having no idea what to do, we went to our local Sigma service center in Hong Kong to have the lense recalibrated. After two days, we got the lense back and it was still 3mm back focused causing 80% of photos to be out of focus. We spoke to Sigma and what advice did they give "You must use ths lens only in manual focus mode and at f5.6 to get good shots. These lenses are like this, there is nothing more we can do". After given that advice, we swiftly refunded the lens and exchanged it for a canon 17-40.

I don't like to put down any brands but after the experience we had, I really feel I ought to share as I think Sigma are getting away with murder selling the products they do for hard earned money and yet have the cheek to patronise the consumers. I have only ever bought L lenses but on this occasion, reccommened Sigma to my friend as she has a low budget. Boy do I regret it.

To all of you who want a good lens, stick to Canon. I strongly believe those reviewers who claim they have excellent Sigma lenses are total amateurs. It's a bit like writing a car review having never tested a Ferrari. How do you know what is good if you have never tested the best ?...

One more thing, even the shop keeper was not surprised when we went back for an exchange. That just says it all.

In the case of canon, they are an expensive brand but they get it right more of the time. There are bad lenses reaching the shop shelves but far fewer than sigma. I have used canon L's for a while and do some pretty geeky tests before I buy. 80% of lenses are excellent. In the case of Sigma, 80% was unacceptable, 10% was passable, 10% was OK but "OK"

I recently purchased a Sigma 17-70 to replace a Canon 24-85 that had front focusing problems when used with my Rebel XSi. My sample of the Sigma has none of the focusing problems mentioned by Pawn_sr. Because of the problems I had with my Canon 24-85, I ran some autofocus tests along with lens resolution tests on both the Sigma and Canon.
The Sigma is sharpest at the telephoto end, but even at f:2.8 at 17mm 100% crops of images look reasonably sharp to me. The Canon was sharpest wide open at 24mm, with performance declining as the focal length increased. Sharpness at 85mm at f:4.5 was fair. The Canon lens looked significantly worse wide open at all focal lengths than at f:8, while the decline in performance as the Sigma's aperture was opened up was less noticeable. In addition pictures taken with the Sigma at all lens openings seem to be more contrasty than those taken with the Canon 24-85. With the small sensor on the Rebel XSi, corners of pictures taken by both lenses didn't look significantly worse than centers.
Focusing speed of the Canon is better than the Sigma, and as others have noted, the Sigma is noisier. Neither lens had any difficulty locking into focus at low light levels. However, the Canon consistently focused 6-10mm in front of the target when I tested its auto focus, while the Sigma focused accurately.
With regard to Pawn_sr's issue with variations in Sigma lens quality, I'd suggest a look at Bob Atkins lens defect survey at his lensplay.com website. It shows that while Sigma lenses are somewhat more likely to have defects than other brands, about 4 of 5 owners do not have problems.

I recently purchased a Sigma 17-70 to replace a Canon 24-85 that had front focusing problems when used with my Rebel XSi. My sample of the Sigma has none of the focusing problems mentioned by Pawn_sr. Because of the problems I had with my Canon 24-85, I ran some autofocus tests along with lens resolution tests on both the Sigma and Canon.

The Sigma is sharpest at the telephoto end, but even at f:2.8 at 17mm 100% crops of images look reasonably sharp to me. The Canon was sharpest wide open at 24mm, with performance declining as the focal length increased. Sharpness at 85mm at f:4.5 was fair. The Canon lens looked significantly worse wide open at all focal lengths than at f:8, while the decline in performance as the Sigma's aperture was opened up was less noticeable. In addition pictures taken with the Sigma at all lens openings seem to be more contrasty than those taken with the Canon 24-85. With the small sensor on the Rebel XSi, corners of pictures taken by both lenses didn't look significantly worse than centers.

Focusing speed of the Canon is better than the Sigma, and as others have noted, the Sigma is noisier. Neither lens had any difficulty locking into focus at low light levels. However, the Canon consistently focused 6-10mm in front of the target when I tested its auto focus, while the Sigma focused accurately.

With regard to Pawn_sr's issue with variations in Sigma lens quality, I'd suggest a look at Bob Atkins lens defect survey at his lensplay.com website. It shows that while Sigma lenses are somewhat more likely to have defects than other brands, about 4 of 5 owners do not have problems.

Having upgraded my camera to a Canon 60D I decided to save up and upgrade my general purpose lens from the Canon 18-55 IS to the Sigma 17-70 (or so I thought), but have had no end of problems with this lens. It was nowhere near as sharp as my old kit lens and I take a lot of landscapes so could see huge differences in the sharpness of leaves on trees, ferns, rocks etc. I spent a month trying it out and then was ill for a month so eventually took it back to Jacobs nearly 3 months after buying it. They would not take it back as I had owned it for 3 months, but they tested it and said it was back focusing, so sent it off to Sigma. 3 weeks later it came back and while it is better, it is still not as sharp or contrasty as my old kit lens, which after 4 years of hard use can now only be used in manual focus mode. I will never buy a Sigma lens again and will save longer and stick with Canon. I will now be selling this lens and investing in either the Canon 17-40 or for more range the 15-85. It is definitely not worth the money I paid for it. The Canon 18-55 IS is far better for overall sharpness and contrast and £200 less. To me, the most important aspect of any lens is not build quality, features etc., but the image quality and with the Sigma 17-70 you can forget that.

Having upgraded my camera to a Canon 60D I decided to save up and upgrade my general purpose lens from the Canon 18-55 IS to the Sigma 17-70 (or so I thought), but have had no end of problems with this lens. It was nowhere near as sharp as my old kit lens and I take a lot of landscapes so could see huge differences in the sharpness of leaves on trees, ferns, rocks etc. I spent a month trying it out and then was ill for a month so eventually took it back to Jacobs nearly 3 months after buying it. They would not take it back as I had owned it for 3 months, but they tested it and said it was back focusing, so sent it off to Sigma. 3 weeks later it came back and while it is better, it is still not as sharp or contrasty as my old kit lens, which after 4 years of hard use can now only be used in manual focus mode. I will never buy a Sigma lens again and will save longer and stick with Canon. I will now be selling this lens and investing in either the Canon 17-40 or for more range the 15-85. It is definitely not worth the money I paid for it. The Canon 18-55 IS is far better for overall sharpness and contrast and £200 less. To me, the most important aspect of any lens is not build quality, features etc., but the image quality and with the Sigma 17-70 you can forget that.